Two-axis variable width mass resolving aperture with fast acting shutter motion

ABSTRACT

A resolving aperture assembly for an ion implantation system has a first plate and a second plate, where the first plate and second plate generally define a resolving aperture therebetween. A position of the first plate with respect to the second plate generally defines a width of the resolving aperture. One or more actuators are operably coupled to one or more of the first plate and second plate and are configured to selectively vary the position the first plate and second plate with respect to one another, thus selectively varying the width of the resolving aperture. A servo motor precisely varies the resolving aperture width and a pneumatic cylinder independently selectively closes the resolving aperture. A downstream position actuator varies a position of the resolving aperture along a path of the ion beam, and a controller controls the one or more actuators based on desired properties of the ion beam.

REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. application Ser. No.15/363,728 filed on Nov. 29, 2016, entitled “TWO-AXIS VARIABLE WIDTHMASS RESOLVING APERTURE WITH FAST ACTING SHUTTER MOTION”, the contentsof which are hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to ion implantation systems, andmore specifically to systems and methods for controlling an aperturewidth for ion beams in ion implantation systems.

BACKGROUND OF THE INVENTION

In the manufacture of semiconductor devices, ion implantation is used todope semiconductors with impurities or dopants. Ion implantation systems(also called ion implanters) are commonly used to treat semiconductorworkpieces, such as silicon wafers, with an ion beam in order to producen or p type extrinsic material doping or to form passivation layersduring fabrication of an integrated circuit. When used for dopingsemiconductors, the ion implanter injects a selected extrinsic ionspecies to produce the desired properties in the semiconductingmaterial. Implanting ions generated from source materials such asantimony, arsenic or phosphorus results in “n type” extrinsic materialwafers, whereas if “p type” extrinsic material wafers are desired, ionsgenerated with source materials such as boron, or indium may beimplanted.

Typical ion beam implanters include an ion source for generatingpositively charged ions from ionizable source materials. The generatedions are formed into a beam and directed along a predetermined beam pathtoward an end station. The ion beam implanter may include beam formingand shaping structures extending between the ion source and the endstation. The beam forming and shaping structures maintain the ion beamand bound an elongated interior cavity or passageway through which thebeam passes en route to the end station. When operating an ionimplanter, this passageway can be evacuated to reduce the probability ofions being deflected from the predetermined beam path as a result ofcollisions with gas molecules.

Trajectories of charged particles of given kinetic energy in a magneticfield will differ for different masses (or charge-to-mass ratios) ofthese particles. Therefore, the part of an extracted ion beam thatreaches a desired area of a semiconductor wafer or other target afterpassing through a constant magnetic field can be made pure, since ionsof undesirable molecular weight will be deflected to positions away fromthe ion beam, whereby implantation of materials other than those desiredcan be avoided. The process of selectively separating ions of desiredand undesired charge-to-mass ratios is known as mass analysis. Massanalyzers typically employ a mass analysis magnet creating a dipolemagnetic field to deflect various ions in an ion beam via magneticdeflection in an arcuate passageway that effectively separates ions ofdifferent charge-to-mass ratios.

For some ion implantation systems, the physical size of the ion beam issmaller than a target workpiece, whereby the ion beam is scanned in oneor more directions in order to adequately cover a surface of the targetworkpiece. Generally, an electrostatic or magnetic based scanner scansthe ion beam in a fast direction and a mechanical device moves thetarget workpiece in a slow scan direction in order to provide sufficientcoverage of the ion beam across the surface of the target workpiece.

SUMMARY OF THE INVENTION

The present disclosure thus provides a system and apparatus forselectively controlling a width of a mass resolving aperture in an ionimplantation system and for selectively blocking the ion beam.Accordingly, the following presents a simplified summary of thedisclosure in order to provide a basic understanding of some aspects ofthe invention. This summary is not an extensive overview of theinvention. It is intended to neither identify key or critical elementsof the invention nor delineate the scope of the invention. Its purposeis to present some concepts of the invention in a simplified form as aprelude to the more detailed description that is presented later.

Aspects of the present invention facilitate ion implantation byperforming angle adjustments without additional components being addedto ion implantation systems. The aspects employ a mass analyzer toperform selected angle adjustments during ion implantation instead ofemploying separate and/or additional components.

In accordance with one aspect of the invention, an ion implantationsystem employs a mass analyzer for both mass analysis and anglecorrection. An ion source generates an ion beam along a beam path. Amass analyzer is located downstream of the ion source that performs massanalysis and angle correction on the ion beam. A resolving apertureassembly is located downstream of the mass analyzer component and alongthe beam path. The resolving aperture assembly comprises a first plateand a second plate, wherein the first plate and second plate generallydefine a resolving aperture therebetween. A position of the first platewith respect to the second plate generally defines a width of theresolving aperture.

One or more actuators are further operably coupled to one or more of thefirst plate and second plate, wherein the one or more actuators areconfigured to selectively vary the position the respective one or moreof the first plate and second plate with respect to one another, thereinselectively varying the width of the resolving aperture. A controller isfurther configured to control the width of the resolving aperture via acontrol of the one or more actuators, wherein the control of the widthof the resolving aperture is based, at least in part, on one or moredesired properties of the ion beam.

According to one example, the one or more actuators are furtherconfigured to selectively position the first plate and second plate toselectively position the resolving aperture in an exit beam path of themass analyzer based on one or more of the selected beam envelope andselected mass resolution. The one or more actuators, for example, arefurther configured to selectively position the first plate with respectto the second plate to selectively close or shutter the resolvingaperture, therein selectively preventing the ion beam from travelingdownstream of the resolving aperture assembly. In one example, the oneor more linear actuators comprise one or more servo motors and one ormore pneumatic cylinders operably coupled to one or more of the firstplate and second plate, wherein the one or more servo motors areconfigured to precisely vary the width of the resolving aperture, andwherein the one or more pneumatic cylinders are configured toselectively close the resolving aperture.

In accordance with another example, a sensing apparatus is configured todetect one or more conditions associated with the ion beam. The one ormore conditions, for example, may be associated with a beam currentand/or one or more fault conditions, and wherein the controller isconfigured to selectively close the resolving aperture via a control ofthe pneumatic cylinder upon the detection of the one or more faultconditions. The controller, for example, is further configured toselectively individually translate the first plate and second plate viaa control of the one or more actuators based on the one or moreconditions sensed by the sensing apparatus.

In another example, a downstream position actuator is configured toselectively vary a position of the resolving aperture along a path ofthe ion beam, wherein the controller is further configured to controlthe position of the resolving aperture along the ion beam path based, atleast in part, on one or more desired properties of the ion beam. Othersystems and methods are also disclosed.

The following description and annexed drawings set forth in detailcertain illustrative aspects and implementations of the invention. Theseare indicative of but a few of the various ways in which the principlesof the invention may be employed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example ion implantation system in accordance withan aspect of the present disclosure.

FIG. 2 is a perspective view of an exemplary resolving aperture assemblyin accordance with another aspect of the disclosure.

DETAILED DESCRIPTION OF THE INVENTION

The present disclosure is directed generally toward a system, apparatus,and method for selectively controlling a width of a mass resolvingaperture in an ion implantation system. Accordingly, the presentinvention will now be described with reference to the drawings, whereinlike reference numerals may be used to refer to like elementsthroughout. It will be understood that the description provided hereinis merely illustrative and that this detailed description should not beinterpreted in a limiting sense. In the following description, forpurposes of explanation, numerous specific details are set forth inorder to provide a thorough understanding of the present invention. Itwill be evident to one skilled in the art, however, that the presentinvention may be practiced without certain of these specific details.Further, the scope of the invention is not intended to be limited by theembodiments or examples described hereinafter with reference to theaccompanying drawings, but is intended to be only limited by theappended claims and substantial equivalents thereof.

It is also noted that the drawings are provided to give an illustrationof some aspects of embodiments of the present disclosure and thereforeare to be regarded as schematic only. In particular, the elements shownin the drawings are not necessarily to scale with each other, and theplacement of various elements in the drawings is chosen to provide aclear understanding of the respective embodiment and is not to beconstrued as necessarily being a representation of the actual relativelocations of the various components in implementations according to anembodiment of the invention. Furthermore, the features of the variousembodiments and examples described herein may be combined with eachother unless specifically noted otherwise.

It is also to be understood that in the following description, anydirect connection or coupling between functional blocks, devices,components, circuit elements or other physical or functional units shownin the drawings or described herein could also be implemented by anindirect connection or coupling. Furthermore, it is to be appreciatedthat functional blocks or units shown in the drawings may be implementedas separate features or circuits in one embodiment, and may also oralternatively be fully or partially implemented in a common feature orcircuit in another embodiment. For example, several functional blocksmay be implemented as software running on a common processor, such as asignal processor. It is further to be understood that any connectionwhich is described as being wire-based in the following specificationmay also be implemented via wireless communication, unless noted to thecontrary.

The present disclosure provides mass resolving aperture assemblyconfigured to provide a variable width of the mass resolving aperture,while incorporating an ion beam shutter into mass resolving apertureassembly. Accordingly, plates defining the mass resolving aperture areconfigured to translate along multiple axes (e.g., both the x-axis andz-axis) of a beamline of an ion implantation system. Thus, the massresolving aperture assembly of the present disclosure is configured toselectively reduce unwanted isotopes in a specific region of an ion beamwhere the unwanted isotopes are present via an articulation of platesalong the multiple axes. Further, the mass resolving aperture assemblyis configured to block or shutter the ion beam via the articulation ofthe plates. Still further, the mass resolving aperture assembly isconfigured to obtain an ion beam profile at various points along thez-axis by selectively translating or scanning the plates in the x-axisand recording a resulting ion beam current measurement associatedtherewith.

In accordance with one aspect of the present disclosure, FIG. 1illustrates an example ion implantation system 100. The system 100 ispresented for context and illustrative purposes, and it is appreciatedthat aspects of the invention are not limited to the described ionimplantation system and that other suitable ion implantation systems ofvaried configurations can also be employed.

The system 100 has a terminal 102, a beamline assembly 104, and an endstation 106. The terminal 102 includes an ion source 108 powered by ahigh voltage power supply 110 that produces and directs an ion beam 112having a selected species to the beamline assembly 104. The ion source108 generates charged ions that are extracted and formed into the ionbeam 112, which is directed along a beam path in the beamline assembly104 to the end station 106.

To generate the ions, a gas of a dopant material (not shown) to beionized is located within a generation chamber 114 of the ion source108. The dopant gas can, for example, be fed into the generation chamber114 from a gas source (not shown). In addition to power supply 110, itwill be appreciated that any number of suitable mechanisms (none ofwhich are shown) can be used to excite free electrons within the iongeneration chamber 114, such as RF or microwave excitation sources,electron beam injection sources, electromagnetic sources and/or acathode which creates an arc discharge within the chamber, for example.The excited electrons collide with the dopant gas molecules and ions aregenerated thereby. Typically, positive ions are generated although thedisclosure herein is applicable to systems wherein negative ions aregenerated as well.

The ions are controllably extracted through a slit 116 in the generationchamber 114 by an ion extraction assembly 118, in this example. The ionextraction assembly 118 comprises a plurality of extraction and/orsuppression electrodes 120 a, 120 b. The ion extraction assembly 118 caninclude, for example, a separate extraction power supply (not shown) tobias the extraction and/or suppression electrodes 120 a, 120 b toaccelerate the ions from the generation chamber 114. It can beappreciated that since the ion beam 112 comprises like chargedparticles, the beam may have a tendency to blow up or expand radiallyoutwardly as the like charged particles repel one another. It can alsobe appreciated that beam blow up can be exacerbated in low energy, highcurrent (high perveance) beams where many like charged particles (e.g.,high current) are moving in the same direction relatively slowly (e.g.,low energy) such that there is an abundance of repulsive forces amongthe particles, but little particle momentum to keep the particles movingin the direction of the beam path. Accordingly, the extraction assembly118 is generally configured so that the beam is extracted at a highenergy so that the beam does not blow up (e.g., so that the particleshave sufficient momentum to overcome repulsive forces that can lead tobeam blow up). Moreover, the beam 112, in this example, is generallytransferred at a relatively high energy throughout the system 100 and isreduced just before a workpiece 122 positioned in the end station 106 topromote beam containment.

The beamline assembly 104 in the present example has a beamguide 124, amass analyzer 126, a scanning system 128, and a parallelizer and/orcorrector component 130 (referred to generally as a parallelizer). Themass analyzer 126 performs mass analysis and angle correction/adjustmenton the ion beam 112. The mass analyzer 126, in this example, is formedat about a ninety degree angle and comprises one or more magnets (notshown) that serve to establish a (dipole) magnetic field therein. As thebeam 112 enters the mass analyzer 124, it is correspondingly bent by themagnetic field such that ions of an inappropriate charge-to-mass ratioare rejected. More particularly, ions having too great or too small acharge-to-mass ratio are deflected into side walls 132 of the massanalyzer 126. In this manner, the mass analyzer 126 mainly allows thoseions in the beam 112 which have the desired charge-to-mass ratio to passthere-through and exit through a resolving aperture 134 of a massresolving aperture assembly 136, details of which will be discussedfurther infra.

The mass analyzer 126 can perform angle corrections on the ion beam 112by controlling or adjusting an amplitude of the magnetic dipole field.This adjustment of the magnetic field causes selected ions having thedesired/selected charge-to-mass ratio to travel along a different oraltered path. As a result, the resolving aperture 134 can be adjustedaccording to the altered path. In one example, the mass resolvingaperture assembly 136 is movable about an x direction (e.g., a directiontransverse to the ion beam 112) so as to accommodate altered pathsthrough the resolving aperture 134.

It will be appreciated that collisions of the ion beam 112 with otherparticles in the system 100 can degrade beam integrity. Accordingly, oneor more pumps (not shown) may be included to evacuate, at least, thebeamguide 124 and mass analyzer 126.

The scanning system 128 in the illustrated example includes a magneticscanning element 138 and a focusing and/or steering element 140.Respective power supplies 142, 144 are operatively coupled to thescanning element 138 and the focusing and steering element 140, and moreparticularly to respective electromagnet pieces 146 a, 146 b andelectrodes 148 a, 148 b located therein. The focusing and steeringelement 140 receives the mass analyzed ion beam 112 having a relativelynarrow profile (e.g., a “pencil” beam in the illustrated system 100). Avoltage applied by the power supply 144 to the plates 148 a and 148 boperates to focus and steer the beam to a scan vertex 150 of thescanning element 138. A voltage waveform applied by the power supply 142(which theoretically could be the same supply as 144) to theelectromagnets 146 a and 146 b then scans the beam 112 back and forth,in this example, therein defining a scanned ion beam 152 (sometimescalled a “ribbon beam”). It will be appreciated that the scan vertex 150can be defined as the point in the optical path from which each beamletor scanned part of the ion beam 112 appears to originate after havingbeen scanned by the scanning element 138.

The scanned beam 112 is then passed through the parallelizer/corrector130, which comprises two dipole magnets 154 a, 154 b in the illustratedexample. The two dipole magnets 154 a, 154 b, for example, aresubstantially trapezoidal and are oriented to mirror one another tocause the beam 112 to bend into a substantially s-shape. Stated anotherway, the two dipole magnets 154 a, 154 b have equal angles and radii andopposite directions of curvature.

The parallelizer 130 causes the scanned beam 112 to alter its path suchthat the ion beam travels parallel to a beam axis regardless of the scanangle. As a result, the implantation angle is relatively uniform acrossthe workpiece 122.

One or more deceleration stages 156 are located downstream of theparallelizer 130 in this example. Up to this point in the system 100,the ion beam 112 is generally transported at a relatively high energylevel to mitigate the propensity for beam blow up, which can beparticularly high where beam density is elevated such as at scan vertex150, for example. The one or more deceleration stages 156, for example,comprise one or more electrodes 158 a, 158 b operable to decelerate thebeam 112. The one or more electrodes 158 a, 158 b are typicallyapertures thru which the ion beam 112 travels, and may be drawn asstraight lines in FIG. 1.

Nevertheless, it will be appreciated that while two electrodes 120 a and120 b, 146 a and 146 b, 148 a and 148 b and 158 a and 158 b arerespectively illustrated in the exemplary ion extraction assembly 118,scanning element 138, focusing and steering element 140 and decelerationstage 156, these elements may respectively comprise any suitable numberof electrodes arranged and biased to accelerate and/or decelerate ions,as well as to focus, bend, deflect, converge, diverge, scan, parallelizeand/or decontaminate the ion beam 112 such as provided in U.S. Pat. No.6,777,696 to Rathmell et al. the entirety of which is herebyincorporated herein by reference. Additionally, the focusing andsteering element 140 may comprise electrostatic deflection plates (e.g.,one or more pairs thereof), as well as an Einzel lens, quadrupolesand/or other focusing elements to focus the ion beam.

The end station 106 then receives the ion beam 112 which is directedtoward the workpiece 122. It is appreciated that different types of endstations 106 may be employed in the implanter 100. For example, a“batch” type end station can simultaneously support multiple workpieces122 on a rotating support structure, wherein the workpieces are rotatedthrough a beam path 160 (also called a beamline) of the ion beam 112until all the workpieces are completely implanted. A “serial” type endstation, on the other hand, supports a single workpiece 122 along thebeam path 160 for implantation, wherein multiple workpieces areimplanted one at a time in serial fashion, with each workpiece beingcompletely implanted before implantation of the next workpiece begins.In hybrid systems, the workpiece 122 may be mechanically translated in afirst direction (the y-direction or so-called “slow scan” direction)while the ion beam 112 is scanned in a second direction (the x-directionor so-called “fast scan” direction) to impart the beam 112 over theentire workpiece 122.

The end station 106 in the illustrated example is a “serial” type endstation that supports the single workpiece 122 along the beam path 160for implantation. A dosimetry system 162, for example, is included inthe end station 106 near the location of the workpiece 122 formeasurements of the ion beam 112 (e.g., measurements may be performedprior to implantation operations). During calibration, the beam 112passes through dosimetry system 162. The dosimetry system 162, forexample, includes one or more profilers 164 that may continuouslytraverse a profiler path 166, thereby measuring the profile of thescanned ion beam 152.

The one or more profilers 164, for example, may comprise a currentdensity sensor, such as a Faraday cup, that measures the current densityof the scanned ion beam 152, where current density is a function of theangle of implantation (e.g., the relative orientation between the ionbeam and the mechanical surface of the workpiece 122 and/or the relativeorientation between the ion beam and the crystalline lattice structureof the workpiece). The current density sensor, for example, moves in agenerally orthogonal fashion relative to the scanned ion beam 152 andthus typically traverses the width of the scabbed ion beam. Thedosimetry system 162, in one example, measures both beam densitydistribution and angular distribution.

A control system 168 (also called a controller) is further provided tocontrol, communicate with, and/or adjust the ion source 108, the massanalyzer 132, the mass resolving aperture assembly 136, the magneticscanner 138, the parallelizer 130, and the dosimetry system 162. Thecontrol system 168 may comprise a computer, microprocessor, etc., andmay be operable to take measurement values of characteristics of the ionbeam 112 and adjust parameters accordingly. The control system 168 canbe coupled to the terminal 102 from which the ion beam 112 is generated,as well as the mass analyzer 126 of the beamline assembly 104, thescanning element 138 (e.g., via power supply 142), the focusing andsteering element 140 (e.g., via power supply 144), and the decelerationstage 154. Accordingly, any of these elements can be adjusted by thecontrol system 168 to facilitate desired ion implantation. For example,the energy level of the ion beam 112 can be adapted to adjust junctiondepths by adjusting the bias applied to electrodes in the ion extractionassembly 118 and the deceleration stage 154, for example.

In accordance with one exemplary aspect, the dosimetry system 162, forexample, may be utilized to shutter the beam 122 during an implant ifthe measured beam current is outside a tolerance range that set inprocess recipe for the particular ion implantation. For example, in aprocess recipe specifying a desired beam current of 20 ma with apredetermined range of +−10%, the control system 168 may be configuredto close the resolving aperture assembly 136 to shutter and hold theimplant, should the measured beam current fall below 18 ma or exceed 22ma. An additional measurement system (not shown, but similar to thedosimetry system 162) may be further used in conjunction with dosimetrysystem 162 in order to detect fast transients or glitches in the beam122 that would otherwise go undetected by the dosimetry system 162.During a glitch, for example, the beam 122 is switched off, theresolving aperture assembly 136 will close or shutter, and the implantwill be kept on hold until the ion beam is stable. For example, U.S.Pat. No. 7,507,977 to Weiguo, et al. describe a system and method ofcontrolling an ion beam in response to an ion beam glitch.

The strength and orientation of magnetic field(s) generated in the massanalyzer 126 can be adjusted, such as by regulating the amount ofelectrical current running through field windings therein to alter thecharge to mass ratio of the beam, for example. The angle of implantationcan be controlled by adjusting the strength or amplitude of the magneticfield(s) generated in the mass analyzer 126 in coordination with themass resolving aperture assembly 136. The control system 168 can adjustthe magnetic field(s) of the mass analyzer 126 and position of theresolving aperture 134 according to measurement data from, in thisexample, the profiler 164. The control system 168 can verify theadjustments via additional measurement data and perform additionaladjustments via the mass analyzer 126 and the resolving aperture 134, ifnecessary.

In accordance with another aspect, the resolving aperture assembly 136of the present disclosure provides a fast-acting shutter motion for theresolving aperture 134, wherein the width of the resolving aperture isfurther variable. Thus, the resolving aperture assembly 136 of thepresent disclosure is operable to control not only the width andposition of the resolving aperture 134 with respect to the massanalyzer, but is further operable to shutter or block the ion beam 112from traveling further downstream toward the end station 106.

Conventionally, two distinctly separate assemblies were provided toaccomplish the shuttering of the ion beam and control of the width ofthe resolving aperture; namely, a rotatable shutter similar to a ballvalve, and a resolving plate having one or more fixed-width apertures,whereby the desired aperture is generally positioned in the center ofthe beamline. An example of a multiple-aperture plate is provided incommonly owned U.S. Pat. No. 7,399,980 to Vanderberg et al., thecontents of which are incorporated by reference in its entirety, herein.Such a multiple-aperture plate provides several discrete widths ofresolving apertures, while further providing an ability to move theresolving aperture transverse to the ion beam in order to modify orcorrect angular orientations of the ion beam. However, additional,separate blocking mechanisms would be conventionally provided in theVanderberg et al. system in order to block the ion beam in variouscircumstances, such as during workpiece placement, faults detected inthe ion beam, etc.

In accordance with several aspects of the present disclosure, the singleresolving aperture assembly 136 is configured to provide a selectivevariation of the width of the resolving aperture 134, to selectivelyvary the relative location of the resolving aperture across (e.g.,transverse in the x-direction) and along (e.g., in the z-direction) thebeamline 160, and to further selectively shutter or block the ion beam112 from being transported beyond the resolving aperture assembly.Unlike the conventional resolving aperture assemblies having a fixedaperture width, the resolving aperture assembly 136 of the presentdisclosure provides the resolving aperture 134 with a continuouslyvariable width. The resolving aperture 134 of the present disclosure canbe further advantageously translated or swept transverse to the beamline160, such that the resolving aperture can be positioned to profile theion beam 112 at various locations across the width of the ion beam.

An example of the resolving aperture assembly 136 of FIG. 1 isillustrated in FIG. 2 as exemplary resolving aperture assembly 200,wherein the resolving aperture assembly is positioned downstream of themass analyzer 126 of FIG. 1. As illustrated in FIG. 2, the resolvingaperture assembly 200 comprises a first plate 202 and a second plate204, wherein the first plate and second plate generally define aresolving aperture 206 therebetween. Accordingly, a position 208 of thefirst plate 202 with respect to the second plate 204 generally defines awidth 210 of the resolving aperture 206, wherein the width of theresolving aperture is selectively variable, as will be discussed furtherinfra.

In accordance with one example, one or more actuators 212 are operablycoupled to one or more of the first plate 202 and second plate 204. Inthe present example, the one or more actuators 212 comprise a firstactuator 214 operably coupled to the first plate 202 and a secondactuator 216 operably coupled to the second plate 204. The one or moreactuators 212 are configured to respectively selectively vary theposition 208 of the first plate 202 and second plate 204 with respect tothe beamline 160 of FIG. 1 and/or one another. The first plate 202 andsecond plate 204 of the resolving aperture assembly 200 of FIG. 2, forexample, in conjunction with the one or more actuators 212 of thepresent disclosure, advantageously provides each of the first and secondplates to be moved either independently of one another or in unison,thereby selectively varying one or more of the width 210 of theresolving aperture 206, or selectively shifting the beamline position218 of the resolving aperture from side to side transverse the ion beam112 of FIG. 1 (e.g., in the x-direction).

In the present example, the first actuator 214 and second actuator 216of FIG. 2 are configured to selectively translate the respective firstplate 202 and second plate 204, either independently, or in unison.Accordingly, the resolving aperture assembly 200 of the presentdisclosure advantageously allows the ion beam 112 of FIG. 1 to beprofiled at almost any location along the width thereof (e.g., in thex-direction), such as in cases when searching for undesirable isotopesassociated with the ion beam.

The control system 168, for example, is further configured to controlthe position 208 of one or more of the first plate 202 and second plate204 shown in FIG. 2 via a control of the one or more actuators 212. Inanother example, the first plate 202 and second plate 204 are configuredto translate generally parallel to the beamline 160 of the ion beam 112(e.g., along the z-axis) to accommodate various species of ions utilizedin implantation. For example, the waist or smallest part of the ion 112beam is different for different species (e.g., boron B-11 and B-10isotopes and arsenic isotopes) as the ion beam exits the mass analyzer124. For boron B-11 and B-10 isotopes, for example, the waist would beat a certain fixed distance down the beamline 160, whereas for a speciessuch as Arsenic, the waist would be in a different location along thebeamline. Thus, the resolving aperture assembly 136 is configured tomove the resolving aperture 134 to various positions along the beamline160 based on the desired species being implanted.

In accordance with one example, the control system 168 of FIG. 1, forexample, can be configured to control one or more of the width 210 andposition 208 of the resolving aperture 206 of FIG. 2 with respect to thebeamline 160, wherein the control of the width of the resolving apertureis based, at least in part, on one or more desired properties of the ionbeam 112. The one or more desired properties of the ion beam 112, forexample, comprise a selected ion beam envelope (e.g., a desired width ofthe ion beam) and a selected mass resolution of the ion beam. Forexample, the one or more actuators 212 of FIG. 2 are configured toselectively position the first plate 202 and second plate 204 toselectively position the resolving aperture 206 in the exit beam path ofthe mass analyzer 124 based on one or more of the selected beam envelopeand selected mass resolution.

In accordance with one example, the one or more actuators 212 of FIG. 2comprise one or more linear actuators 218. The one or more actuators 218associated with the resolving aperture assembly 200, for example, areconfigured to position the first plate 202 with respect to the secondplate 204 to selectively close or shutter the resolving aperture 206,therein selectively preventing the ion beam 112 of FIG. 1 from travelingdownstream of the resolving aperture assembly. The one or more linearactuators 212 associated with the first plate 202 and second plate 204of FIG. 2, for example, comprise one or more of a servo motor 220 and apneumatic cylinder 222 operably coupled to one or more of the firstplate and second plate. In the present example, a first servo motor 224and first pneumatic cylinder 226 are operably coupled to the firstplate, and a second servo motor 228 and second pneumatic cylinder 230are operably coupled to the second plate. The first servo motor 224 andsecond servo motor 228 are configured to precisely vary the width 210and position 208 of the resolving aperture along the beamline, while thefirst pneumatic cylinder 226 and second pneumatic cylinder 230 areconfigured to quickly close and/or open the resolving aperture 206.

For example, when associated with a recovery from an error associated anion beam glitch, a location on the workpiece at which the error hasoccurred on the workpiece is known. Accordingly, in recovering from theerror, the implantation is placed in a hold state, and the ion beam isshuttered. The control system is further configured to re-position theworkpiece to the known location at which the error occurred, and just asthe workpiece arrives at the known location, the resolving aperture 206is quickly opened via one or more of the first pneumatic cylinder 226and second pneumatic cylinder 230, whereby the implantation of ions cancontinue in a generally seamless manner.

The first servo motor 224 and second servo motor 228, for example, arefurther configured to independently vary the position 208 and width 210of the aperture 206 by independently positioning the first plate 202 andsecond plate 204 with respect to one another or the ion beam.

Furthermore, one or more linear potentiometers 232 can be furtherassociated with the one or more linear actuators 212 to providepositional feedback, wherein the one or more linear potentiometers areconfigured to provide a position of one or more of the first plate 202and second plate 204 to the controller 168 of FIG. 1. It should be notedthat while the one or more linear actuators 212 are described as servomotors and/or pneumatic cylinders, various other types of electricmotor-drive actuators, pneumatic actuators, and hydraulic linearactuators are also contemplated as falling within the scope of thepresent disclosure. Likewise, while one or more linear potentiometers232 are specifically described, various other feedback mechanisms arecontemplated to provide the positional information to the controller.The one or more linear potentiometers 232, for example, can furtherprovide a signal to the control system 168 to indicate an initialreference position associated with the first plate 202 and second plate204. Once the initial reference position known, the first servo motor224 and second servo motor 228 can provide respective linear positionalinformation.

In accordance with another exemplary aspect of the disclosure, thedosimetry system 162 of FIG. 1 can be configured as a sensing apparatus234 to detect one or more conditions associated with the ion beam 112.The one or more conditions, for example, can comprise one or more faultconditions (e.g., an undesirable current of the ion beam 112), andwherein the controller 168 is configured to selectively close theresolving aperture 134 via a control of the one or more pneumaticcylinders 222 of FIG. 2 upon the detection of the one or more faultconditions.

Furthermore, the controller 168 can be configured to selectivelyindividually translate the first plate 202 and second plate 204 of FIG.2 via a control of the one or more actuators 212 based on the one ormore conditions sensed by the sensing apparatus 234, such as anindication from the sensing apparatus that an undesirable isotope ispresent in the ion beam 112.

Accordingly, the first plate 202 and second plate 204 of the resolvingaperture assembly 200 are configured to quickly and selectively shutteror block the ion beam 112 (e.g., in a pinching or scissor-like motion)from any aperture width 210 via the one or more actuators 212, whilefurther advantageously providing the aforementioned independentvariation of the position 208 and width 210 of the resolving aperture206.

Thus, in accordance with the present disclosure, the first plate 202 andsecond plate 204 of the resolving aperture assembly 200, for example,may be considered as shutters, whereby a first edge 240 and second edge242 of the respective first plate and second plate are configured toconverge toward one another to provide an overlap (not shown). Forexample, one or more of the first edge 240 and second edge 242 comprisea rabbit feature (not shown), whereby the first plate 202 and secondplate 204 overlap each other (e.g., half the overlap distance in thecase of both the first plate and second plate having the rabbitfeature). For example, for a 6 mm total overlap of the first plate 202and second plate 204, each rabbit would have a depth of approximately 3mm. As such, shuttering or entirely blocking of the ion beam 112 of FIG.1 may be achieved.

In accordance with another example, the first plate 202 and second plate204 of FIG. 2 are coupled to a respective first shaft 250 and secondshaft 252, whereby the one or more actuators 212 are configured totranslate the respective first shaft and second shaft. The first plate202 and second plate 204, for example, are fixedly coupled to therespective first shaft 250 and second shaft 252.

It is further noted that the first plate 202 and second plate 204 aregenerally exposed to the ion beam 112 of FIG. 1, whereby the first plateand second plate can be heated by the ion beam. Accordingly, the firstshaft 250 and second shaft 252 of FIG. 2, for example, can be furthercooled, whereby a cooling fluid (e.g., water) passes through a channel(not shown) in the respective first shaft and second shaft. The firstshaft 250 and second shaft 252, for example, are comprised of a metal,and the first plate 202 and second plate 204 are comprised of graphite,whereby the metal cools the respective first plate and second plate viathermal conduction therebetween. The first shaft 250 and second shaft252, for example, can further be operably coupled to a wall of a chamberthat generally encloses the beamline assembly 104 via a vacuumfeedthrough, whereby circulation of the cooling fluid may be achieved bypumps or other mechanisms in an external environment.

Accordingly, the first plate 202 and second plate 204 are indirectlycooled via the first shaft 250 and second shaft 252. The first shaft 250and second shaft 252, for example, can pass through respective vacuumfeedthroughs, whereby the one or more actuators 212 can also be providedin the external environment.

Thus, the present disclosure provides a resolving aperture assembly 200having a variable width mass resolving aperture, along with afast-acting shuttering capability, wherein the mass resolving apertureassembly is further configured to translate the resolving aperture alongthe beamline.

Although the invention has been illustrated and described with respectto one or more implementations, alterations and/or modifications may bemade to the illustrated examples without departing from the spirit andscope of the appended claims. In particular regard to the variousfunctions performed by the above described components or structures(blocks, units, engines, assemblies, devices, circuits, systems, etc.),the terms (including a reference to a “means”) used to describe suchcomponents are intended to correspond, unless otherwise indicated, toany component or structure which performs the specified function of thedescribed component (e.g., that is functionally equivalent), even thoughnot structurally equivalent to the disclosed structure which performsthe function in the herein illustrated exemplary implementations of theinvention. In addition, while a particular feature of the invention mayhave been disclosed with respect to only one of several implementations,such feature may be combined with one or more other features of theother implementations as may be desired and advantageous for any givenor particular application. The term “exemplary” as used herein isintended to imply an example, as opposed to best or superior.Furthermore, to the extent that the terms “including”, “includes”,“having”, “has”, “with”, or variants thereof are used in either thedetailed description and the claims, such terms are intended to beinclusive in a manner similar to the term “comprising”.

1. An ion implantation system comprising: an ion source that generatesan ion beam having a selected species; a mass analyzer positioneddownstream of the ion source that generates a magnetic field accordingto a selected charge-to-mass ratio and an angle adjustment; a resolvingaperture assembly positioned downstream of the mass analyzer, theresolving aperture assembly comprising: a first plate and a secondplate, wherein the first plate and second plate define a resolvingaperture therebetween, wherein a position of the first plate withrespect to the second plate defines a width of the resolving aperture;and one or more actuators operably coupled to one or more of the firstplate and second plate, wherein the one or more actuators are configuredto selectively vary the position the respective one or more of the firstplate and second plate with respect to one another, therein selectivelyvarying the width of the resolving aperture, wherein the one or moreactuators comprise a servo motor and a pneumatic cylinder operablycoupled to one or more of the first plate and second plate; and acontroller configured to control the width of the resolving aperture viaa control of the one or more actuators, wherein the control of the widthof the resolving aperture is based, at least in part, on one or moredesired properties of the ion beam.
 2. The ion implantation system ofclaim 1, wherein the one or more desired properties of the ion beamcomprise a selected ion beam envelope and a selected mass resolution ofthe ion beam.
 3. The ion implantation system of claim 2, wherein the oneor more actuators are further configured to selectively position thefirst plate and second plate to selectively position the resolvingaperture in an exit beam path of the mass analyzer based on one or moreof the selected beam envelope and selected mass resolution.
 4. The ionimplantation system of claim 3, wherein the one or more actuatorscomprise one or more linear actuators.
 5. The ion implantation system ofclaim 1, wherein the one or more actuators are further configured toposition the first plate with respect to the second plate to selectivelyclose the resolving aperture, therein selectively preventing the ionbeam from traveling downstream of the resolving aperture assembly. 6.The ion implantation system of claim 5, wherein the servo motor isconfigured to vary the width of the resolving aperture, and wherein thepneumatic cylinder is configured to selectively close the resolvingaperture.
 7. The ion implantation system of claim 6, further comprisinga sensing apparatus configured to detect one or more conditionsassociated with the ion beam.
 8. The ion implantation system of claim 7,wherein the one or more conditions are associated with one or more faultconditions, and wherein the controller is configured to selectivelyclose the resolving aperture via a control of the pneumatic cylinderupon the detection of the one or more fault conditions.
 9. The ionimplantation system of claim 8, wherein the one or more fault conditionsare associated with an undesirable current of the ion beam.
 10. The ionimplantation system of claim 7, wherein the controller is configured toselectively individually translate the first plate and second plate viaa control of the one or more actuators based on the one or moreconditions sensed by the sensing apparatus.
 11. The ion implantationsystem of claim 10, wherein the one or more conditions comprise an ionbeam current associated with an undesirable isotope.
 12. The ionimplantation system of claim 1, further comprising a focusing componentpositioned downstream of the mass analyzer and upstream of the resolvingaperture, wherein the focusing component is configured to converge theion beam.
 13. The ion implantation system of claim 12, wherein thefocusing component is configured to converge the ion beam to a minimumvalue at a position proximate to the resolving aperture.
 14. (canceled)15. The ion implantation system of claim 1, further comprising one ormore linear potentiometers, wherein the one or more linearpotentiometers are configured to provide a position of one or more ofthe first plate and second plate to the controller.
 16. The ionimplantation system of claim 1, wherein the servo motor and pneumaticcylinder are configured to independently vary the position the firstplate and second plate with respect to one another.
 17. The ionimplantation system of claim 1, further comprising a downstream positionactuator configured to selectively vary a position of the resolvingaperture along a path of the ion beam, wherein the controller is furtherconfigured to control the position of the resolving aperture along thepath of the ion beam based, at least in part, on one or more desiredproperties of the ion beam.
 18. A resolving aperture assembly for an ionimplantation system, the resolving aperture assembly comprising: a firstplate; a second plate; and one or more actuators operably coupled to oneor more of the first plate and second plate, wherein the one or moreactuators comprise a servo motor and a pneumatic cylinder operablycoupled to one or more of the first plate and second plate, wherein thefirst plate and second plate define a resolving aperture therebetween,wherein a position of the first plate with respect to the second platedefines a width of the resolving aperture, and wherein the one or moreactuators are configured to selectively vary the position the firstplate and second plate with respect to one another, therein selectivelyvarying the width of the resolving aperture.
 19. The resolving apertureassembly of claim 18, wherein the one or more actuators comprise one ormore linear actuators.
 20. The resolving aperture assembly of claim 19,wherein the wherein the servo motor and pneumatic cylinder areconfigured to independently vary the position the first plate and secondplate with respect to one another.
 21. The resolving aperture assemblyof claim 20, further comprising one or more linear potentiometerswherein the one or more linear potentiometers are configured todetermine a position of one or more of the first plate and second plate.22. The resolving aperture assembly of claim 20, wherein the servo motoris configured to vary the width of the resolving aperture, and whereinthe pneumatic cylinder is configured to selectively close the resolvingaperture.
 23. The resolving aperture assembly of claim 18, furthercomprising a controller configured to selectively vary the width of theresolving aperture via a control of the one or more actuators.